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<title>Crispy Plotter Documentation: VarList: Class TVar</title>
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<a name="TVar"></a><h1 class="cio">Class TVar</h1>
<table class="sections wide_list">
<tr>
<td><a class="section"  href="#%40Description">Description</a></td><td><a class="section"  href="#%40Hierarchy">Hierarchy</a></td><td><a class="section"  href="#%40Fields">Fields</a></td><td><a class="section"  href="#%40Methods">Methods</a></td><td><a class="section"  href="#%40Properties">Properties</a></td></tr></table>
<a name="%40Description"></a><h2 class="unit">Unit</h2>
<p class="unitlink">
<a   href="VarList.html">VarList</a></p>
<h2 class="declaration">Declaration</h2>
<p class="declaration">
<code>type TVar = class(TObject)</code></p>
<h2 class="description">Description</h2>
<p>
TVar represents a variable, which can be referenced in an expression. It has a name, description and reference counter. When the user enters a new expression, variables from the last user input are not deleted, but their reference counter is first set to 0 and then incremented with each reference to this variable in the expression. After expression evaluation only variables with a reference counter of 0 are deleted. That way a variable and its value survive when a user modifies an expression slightly. Variables are used for the following means:

<p></p>

<pre class="preformatted">
    - User function argument x: A user entered function returns for an
      arbitrary x value a y value. This set of points are drawn by the
      plotter.
    - Symbolic constants e and pi: These constants are handled as write
      protected variables.
    - Parameters: The user can specify implicitly additional parameters.</pre>

<p></p>
<a name="%40Hierarchy"></a><h2 class="hierarchy">Hierarchy</h2>
<ul class="hierarchy"><li class="ancestor">TObject</li>
<li class="thisitem">TVar</li></ul><h2 class="overview">Overview</h2>
<a name="%40Fields"></a><h3 class="summary">Fields</h3>
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<td class="visibility"><a   href="legend.html"><img  src="protected.gif" alt="Protected" title="Protected"></a></td>
<td class="itemcode"><code><b><a   href="VarList.TVar.html#FName">FName</a></b>: String;</code></td>
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<td class="visibility"><a   href="legend.html"><img  src="protected.gif" alt="Protected" title="Protected"></a></td>
<td class="itemcode"><code><b><a   href="VarList.TVar.html#FProtected">FProtected</a></b>: Boolean;</code></td>
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<td class="visibility"><a   href="legend.html"><img  src="protected.gif" alt="Protected" title="Protected"></a></td>
<td class="itemcode"><code><b><a   href="VarList.TVar.html#RefCount">RefCount</a></b>: Integer;</code></td>
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<td class="visibility"><a   href="legend.html"><img  src="public.gif" alt="Public" title="Public"></a></td>
<td class="itemcode"><code><b><a   href="VarList.TVar.html#Value">Value</a></b>: <a   href="ResConst.html#TFloat">TFloat</a>;</code></td>
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<td class="visibility"><a   href="legend.html"><img  src="public.gif" alt="Public" title="Public"></a></td>
<td class="itemcode"><code><b><a   href="VarList.TVar.html#Desc">Desc</a></b>: String;</code></td>
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<a name="%40Methods"></a><h3 class="summary">Methods</h3>
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<td class="visibility"><a   href="legend.html"><img  src="public.gif" alt="Public" title="Public"></a></td>
<td class="itemcode"><code>Constructor <b><a   href="VarList.TVar.html#Create">Create</a></b>(AName: String; AValue: <a   href="ResConst.html#TFloat">TFloat</a>; ADesc: String; AProtected: Boolean);</code></td>
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<td class="visibility"><a   href="legend.html"><img  src="public.gif" alt="Public" title="Public"></a></td>
<td class="itemcode"><code>function <b><a   href="VarList.TVar.html#GetIDName">GetIDName</a></b>: string;</code></td>
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<a name="%40Properties"></a><h3 class="summary">Properties</h3>
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<td class="visibility"><a   href="legend.html"><img  src="public.gif" alt="Public" title="Public"></a></td>
<td class="itemcode"><code>property <b><a   href="VarList.TVar.html#IsProtected">IsProtected</a></b>: Boolean read <a   href="VarList.TVar.html#FProtected">FProtected</a>;</code></td>
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<td class="visibility"><a   href="legend.html"><img  src="public.gif" alt="Public" title="Public"></a></td>
<td class="itemcode"><code>property <b><a   href="VarList.TVar.html#Name">Name</a></b>: String read <a   href="VarList.TVar.html#FName">FName</a>;</code></td>
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<h2 class="description">Description</h2>
<h3 class="detail">Fields</h3>
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<td class="visibility"><a   href="legend.html"><img  src="protected.gif" alt="Protected" title="Protected"></a></td>
<td class="itemcode"><a name="FName"></a><code><b>FName</b>: String;</code></td>
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<tr><td colspan="2">
<p>
variable name</p>
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<td class="visibility"><a   href="legend.html"><img  src="protected.gif" alt="Protected" title="Protected"></a></td>
<td class="itemcode"><a name="FProtected"></a><code><b>FProtected</b>: Boolean;</code></td>
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&nbsp;</td></tr>
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<td class="visibility"><a   href="legend.html"><img  src="protected.gif" alt="Protected" title="Protected"></a></td>
<td class="itemcode"><a name="RefCount"></a><code><b>RefCount</b>: Integer;</code></td>
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<tr><td colspan="2">
<p>
Number of references in one expression </p>
<h6 class="description_section">See also</h6>
<dl class="see_also">
  <dt><a class="normal"  href="VarList.TVar.html">TVar</a></dt>
  <dd>TVar represents a variable, which can be referenced in an expression.</dd>
</dl>
</td></tr>
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<table class="detail wide_list">
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<td class="visibility"><a   href="legend.html"><img  src="public.gif" alt="Public" title="Public"></a></td>
<td class="itemcode"><a name="Value"></a><code><b>Value</b>: <a   href="ResConst.html#TFloat">TFloat</a>;</code></td>
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<tr><td colspan="2">
<p>
Value of variable</p>
</td></tr>
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<td class="visibility"><a   href="legend.html"><img  src="public.gif" alt="Public" title="Public"></a></td>
<td class="itemcode"><a name="Desc"></a><code><b>Desc</b>: String;</code></td>
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<p>
Description of value</p>
</td></tr>
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<h3 class="detail">Methods</h3>
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<td class="visibility"><a   href="legend.html"><img  src="public.gif" alt="Public" title="Public"></a></td>
<td class="itemcode"><a name="Create"></a><code>Constructor <b>Create</b>(AName: String; AValue: <a   href="ResConst.html#TFloat">TFloat</a>; ADesc: String; AProtected: Boolean);</code></td>
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&nbsp;</td></tr>
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<table class="detail wide_list">
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<td class="visibility"><a   href="legend.html"><img  src="public.gif" alt="Public" title="Public"></a></td>
<td class="itemcode"><a name="GetIDName"></a><code>function <b>GetIDName</b>: string;</code></td>
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<tr><td colspan="2">
<p>
Returns name of variable in lower case depending on <a class="normal"  href="VarList.html#CaseSensitiveMatch">CaseSensitiveMatch</a></p>
</td></tr>
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<h3 class="detail">Properties</h3>
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<td class="visibility"><a   href="legend.html"><img  src="public.gif" alt="Public" title="Public"></a></td>
<td class="itemcode"><a name="IsProtected"></a><code>property <b>IsProtected</b>: Boolean read <a   href="VarList.TVar.html#FProtected">FProtected</a>;</code></td>
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<tr><td colspan="2">
&nbsp;</td></tr>
</table>
<table class="detail wide_list">
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<td class="visibility"><a   href="legend.html"><img  src="public.gif" alt="Public" title="Public"></a></td>
<td class="itemcode"><a name="Name"></a><code>property <b>Name</b>: String read <a   href="VarList.TVar.html#FName">FName</a>;</code></td>
</tr>
<tr><td colspan="2">
&nbsp;</td></tr>
</table>
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